Dielectric properties of CaNdAlO sub 4 at microwave frequencies

Journal Article · Wed Jul 01 00:00:00 EDT 1992 · Journal of Applied Physics; (United States)

DOI:https://doi.org/10.1063/1.352162· OSTI ID:7110934

Konopka, J; Wolff, I ^[1]; Lewandowski, S J ^[2]

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1. Universitaet Duisburg ATE-SFB254, 4100 Duisburg 1, P.O. Box 101503 (Germany)
2. Instytut Fizyki PAN, Al.Lotnikow 32, PL 02-668 Warszawa (Poland)

Dielectric properties of CaNdAlO{sub 4} monocrystals, a prospective substrate material for the deposition of high-{ital T}{sub {ital c}} superconductors, were measured with high accuracy at microwave frequencies from 8 to 40 GHz in the temperature range from 10 to 300 K by measuring the resonant frequencies of a completely filled resonant cavity. The material was found to be highly anisotropic. At 300 K it exhibits the dielectric constant along {ital c} axis {epsilon}{sup {prime}}{sub {ital c}} = 17.68, while the dielectric constant in the {ital a}-{ital b} plane is {epsilon}{prime}=19.62, and loss tangent tan {delta}{sub {ital c}} {congruent} tan {delta} {congruent} 5.1{times} 10{sup {minus}4}. Both {epsilon}{sup {prime}}{sub {ital c}} and {epsilon}{prime} depend strongly on temperature and their thermal coefficients have opposite signs, apparently a unique property of CaNdAlO{sub 4}. Below 160 K microwave losses caused by electric field perpendicular to the optical {ital c} axis increase with decreasing temperature, exhibiting a maximum near 65 K followed by a minimum at 30 K. It is suggested that neodymium ions in CaNdAlO{sub 4} at lower temperatures become magnetically ordered, causing an increase of magnetic permeability {mu}{sup {prime}}{sub {ital c}} {gt} 1 and a significant increase of magnetic losses at microwave frequencies. A crystallographic phase transition below 60 K cannot also be excluded.

• OSTI ID: 7110934
• Journal Information: Journal of Applied Physics; (United States), Journal Name: Journal of Applied Physics; (United States) Vol. 72:1; ISSN 0021-8979; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
DIELECTRIC PROPERTIES
ELECTRICAL PROPERTIES
ELECTROMAGNETIC RADIATION
ENERGY LOSSES
LOSSES
MICROWAVE RADIATION
NEODYMIUM COMPOUNDS
NEODYMIUM OXIDES
OXIDES
OXYGEN COMPOUNDS
PERMITTIVITY
PHYSICAL PROPERTIES
RADIATIONS
RARE EARTH COMPOUNDS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K